Compressed air driers of the kind set out above are well known in the art and may be used for drying (and cleaning) compressed air in vehicles or in stationary systems, the former application being of most interest in the present case.
The basic design and function of the air drier forming the basis for the present invention are shown in the British Pat. No. 2 050 195 and in the European Patent Application No. 81201271.4.
The use of a cartridge, filled with filter material and dessicant, in the reservoir forming part of the drying tower of the air drier is also known.
Furthermore, it is known (see for example U.S. Pat. No. 2,790,512) that it is advantageous for utilizing the drying function of the dessicant to have a long and comparatively narrow path for the air through the desiccant rather than a short and wide path. In FIG. 5 of said U.S. Pat. No. 2,790,512 the possibility of obtaining the desired long path within a comparatively low tower by accomplishing a winding path for the air is suggested.